Multiple switch-board



(No Model.)

G. K-BLLOGG. MULTIPLE SWITCH BOARD. l

Alu n UNITED STATES -rrrcn.

MILo G. KELLOGG, or HYDE PARK, I LLiNoisf MULTIPLE SWITCH-BOARD.

SPECIFICATIO forming part of Letters Patent No. 382,475, dated May 8, 1888. l y Application filed Apri1 18,1887. SeralNo. 235,143. (No model.) v

T0 @ZZ vwhom it may concern:

Be it known that I, MILo G. KELLOGG, of Hyde Park, Illinois, have invented 'certain new and useful Improvementsjin Multiple Switch-Boards for Telephone-Exchanges, of which-the following is a full, clear, concise,

.and exact description, reference being had to the accompanying drawings, forming apartof this specification.

My invent-ion relates especially to a telephoneexchange system in which the subscribers lines are single wires.

It consists, first, of a multiple-switchboard system of operating anl exchange and testing at any board to determine whether any given line is in use, which system I shall hereinafter describe and claimin detail.

It consists, secondly, of a certain construction of spring-jack switches and test-bolts,- which I shall hereinafter describe and claim in detail, said invention` in spring-jack switches and test-bolts being applicable to said multipleeswitch-board system mentioned above and to other systems of telephone-exchange switchboards.

. It consists, thirdly, of an operators centralottce system of cords', with plugs, switches, keys, clearing out lannunciators, telephone, calling generator or battery, and circuits for answering, calling, switching, and clearing outv subscribers. lines, which I shall hereinafter describe and claim in detail', said. system being applicable to said multiple-switchboard sysv tem mentioned above and to other systems of 35 telephone-exchange switch-boards.

In my multiple-switchboard system -Iplace as manyswitch-boards in the central oflce asare found necessary or desirablein order-to properly answer the calls and connect and disconnect the subscribers lines. On each boardl place for each telephone-line which centers at the office a spring-jack or similar switch having two insulated contact-points normally in contact, said switch being adapted to receive a plug, and when the plug is inserted to disconnect the contact points and connect one of them to the flexible conducting-cord attached to the plug, and when the plug is withdrawn to again. connect the contactpoints. On each board I also place for each of said telephoneshown and described. f on aboardmay be adjacent to the spring-jack.

lines two test-bolts or contact-pieces insulated from each other and from the other parts of theapparat'us, except by conducting-wires, as The tcstbolts of aline switch of the line, or they may be placed ,in any other situation, provided they are Vso marked or located that the operator may knowl to what linel they belong The switches of a line on the different boards may be calledva series of switches,77 and the test-bolts of a line on the different boards vmay be called 'a series of test-bolts.7 As there are two testbolts foreach line on each board, they may also be called a series of double test-bolts.

Figures l? andlbof the drawings are front views of sections ofy two multiple switchboards, to which the same wires are connected. Fig.l 2 shows a coinpletediagram ofthe boards with their connections, and with allthe centraloffice apparatus, circuits, and connections nec-v essary to operate 'them -according to my invention.

Inthe drawings like parts and apparatus are indicated by thesame letters of reference.

In Fig. 2, A is'a sectional view ofthe switchboard shown in Fig. la, as indicated by line d e, and A is a sectional view of the switch-board shown in Fig. 1b, as indicated by line d e.

a b represent rubber strips, of the shape substantially as shown, on which. the metal parts and at-the edges of the strips adapted to receive the switch-plugs. The contact-springs g g are mounted in the rear of and are parallelto the holesl l, to which they'belong, as shown. VThe contact-points h h of the springlevers pass through the rubber strips and have` connecting-pieces h h', as shown.

The switch-plugs are substantially as shown.

'The several parts mentioned above-are so shaped,arranged, and adjusted that when a plug is inserted intofany. of the holes it raises the contact-spring in 'therear of the hole from the. contact-point, (on-which it normally rests,)

and its cord is connected with the spring only.l

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Each section of a rubber strip,with its contact-spring, contact-point, and the hole,l all arranged and operating as above, may be called a spring-jack switch. The rubber strips are placed one above the other, as shown. The lower edge of one strip, therefore, provides the upper edges of the holes in the strip which is below it. It is not necessary that these holes should be actually square. They may be of any rectilinear shape adapted to the shapes and arrangement of the parts used.

ij, Src., are the two test-bolts of a line on a board. For convenience they are placed one above-the other and to the right of the springjack switch ot' their line and on the front of their rubber strip. They are connected to their line as shown in Fig. 2, and as will hereinafter be described.

S S', Fig. 2, are operators systems of cords, with plugs, keys, switches, clearingout annunciators, operators telephone, signaling generator or battery, &c. One system is shown at each board, and is intended for one operator. Only one pair of cords, with its plugs, switch, key, and clearingout annunciator, is shown in ea'ch system. Others could be added in a manner which will be apparent to those skilled in the art.

D D are the two switch-plugs connected to the pair of cords.

m m are the metal pieces ofthe plugs, adapted to be inserted into the switches.

n n are connecting-pieces.

o is a metal piece connected to the ground and on which theplugs normally rest, asshown, and by which the cords are normally connected to the ground.

Y is a looping-in switch.

y y and z z are contact-bolts ot the switch, on which the operator may at will place the switchlevers.

k is a calling'key. A switch `or similar device might be used in its place.

c is a clearing-out annunciator.

B is the operators signaling-generator, and tis her telephone outfit. The circuits are substantially as shown.

T 'I' are operators testing systems at the two boards-one at each board.

C is the rubber handle of the test-plug.

p g are two contact'pieces, so made, placed, and adj usted that the operator can readily connect them simultaneously to any two doublel test-bo1ts, ij, of her board-as, for instance, p to i and q toj, respectively, or the reverse.

E is an electric bell or other test-receiving instrument, and B is an electric battery, both in a loop which connects the two contactpiecesp q, as shown.

The connection between the apparatus E and B and the plug is by flexible conductor of sucient length, so that the operater may apply the contact-pieces of the plug to any pair of test-bolts ij at her board. Ihe bell and battery should preferably be adjusted to each other so that the bell will respond When the battery is closed through ashort cirtest-bolts is opened.

cuit, but will not respond when the battery is closed through a circuit of considerable resistance.

Each operator has one testing system and one cord system. They should be placed in convenient arrangement at the board which she attends, so that'she can conveniently operate the exchange system.

Two subscribers lines areshown in the drawings. They are marked line No. 1 and line No. 2. They are single-circuit wires grounded at the subscribers stations and passing through their series of switches on the boards, and thence through their calling-annuuciator and to ground in the usual manner and as shown. The other wires would be connected to their switches in like manner. Other boards might be added, and the circuit of a line through its series of switches on the different boards would be such as is usual.

To each subscribers line, after it enters the central office and before it passes to any of the springjack switches, I connect one of its series of test-bolts on each board, either by running the line directly to them or by a branch or branch wires. 6,with its branches, connects line No. 1, as above,tothe testbolts. I also connect each subscribers line, after it has passed through its series of springjack switches and before it passes to its annunciator and ground, to the other bolt of its series of test-bolts on each of the boards; 3, with its branches, connects line No. 1, as above, to its test-bolts. similar manner to its test-bolts by wires 1- and rm and their branches, as shown.

. It is evident that when a switch-plug is inserted into any spring-jack switch of a line the line is opened between the contact-pieces y h of the switch, and is therefore disconnected from the ground and is conncctedto the flexible cord attached to the plug. It is also evident that when there is no plug in any switch of a series of a line there is a completev circuit through the switch boards from any test-bolt i of the line to its corresponding testbolt, j, and that when there is a plug in any switch of the line the circuit between the two If the operator, therefore, applies her test-plug to any pair of testbolts ij, as indicated, and the bell responds, she knows that the circuit between these testbolts is not open, and that the line is not switched for use at any other board. p bell does not respond, she knows that the line is switched for use. It is, however, evident that when the operator makes a test and the line is in use there will bea completed circuit through her test apparatus from one test-boltv and thence tothe ground, and from the ground at the distant end of the line, and also from the ground at the distant end of the line which is connected to it through thelines to the other test-bo1t. The bell and battery should be adjusted to the circuits so that the bell will not respond when closed through such a resistance. In practice about one cell of battery and a Line No. 2 is also connected in a- If the,

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' requirements of the system.

' of the cords.

The method of operating the exchange system at either board, including answering calls, making connections, sending signals, clearingout connections,.&c., issuch as will be apparent on an examination of the yapparatus and circuits shown. n I.

It isevident that when two subscribers are connected together for conversation,'orwhen the switch-plug is in theswitch of one line,the operator can, by movingthe switch Y of the cords used, loop her telephone into the circuit The crosspieces ofthe switchesY maybe of rubber or other similar material, as is usual. The levers of the switchcsYshould remain on y y, except when the operator is using hcrtelephone with the 'cords to which the switch belongs. n n

`Gr in each case `in the drawings represents the ground-connection. 4

I claim as mylnvention and desire to secure by Letters Patent- 1. The combination of two or more strips'of insulating material placed one above the other, each having several spring-jack parts mounted thcreon,each part containing a springlever placed transverse to the front 0'1" thestrip, yand a contact-point normally in contact with the spring-lever, with transverse rectilinearI holes along oneof the edges of -e'ach of saidl strips, oneholcin front oi' each of said levers,

whereby the edge ofone strip provides oneofl the sides of the holes of another strip, substantially as and'for the purpose set forth. n

2. The combination of spring-jack switches mounted on ank insulating-strip, and having their plu g-holes th rough the front of said strip, withy pairs of test bolts or pieces, one pair for each switch, and each pair being mounted on the front of t-he said strip adjacent to its switch,

whereby the operator may knowto what switch each pair ot' test-bolts corresponds, substantially as and for the purpose set forth.

3. In a telephone system, a telephone-Aline, a switching device in the circuit of said line, adapted to open andclose said line at its contact-points, and a pair of test-bolts, one ofthe bolts being connected to the line on one side of the 'switching device and the other boltbeing connected tothe line on the other side, in combination with a testing plug or device having two contact-points connected by a loopin which is abattery and a test-receiving instrument, said Ycontact-points being adapted to be,

Abrought into contact with said test-bolts, substantially as and for the purpose set forth.

4. In a telephone system, a telephone-line, two or more switching devices in the circuit of said line, each adapted to open and close said line-at its contactpoints, and'a pair of test-bolts,v one of the bolts being connected= to,

the line onone side of the switching devices and the other bolt being connected to the line on the other side of the switching devices, in combination with a test plug or device hav- Iing two contact-,points connected lby-aloopfin which is a battery and a test-receiving instru-r ment,said plug contact-points being adapted `tobe brought into cntact with said test-bolts, whereby the operator mayldetermine whether` `or not the circuit from one test-bolt tothe ,other isopened at some one of the switching devices.

5. In atelephonesystem, two or moretele- .y Y

phone-lines, each having two or more switch, ing devices in its circuit, each switchingdevice being adapted in the operation of the system to open and close its line at its contact-points, and pairs of test-bolts, one pair for each line,

one bolt of each pair being lconnected to its. 1

' line on kone side of itsfswitching devices' and the other bolt being connected to its line on the other side of its switchingdevices, in com-- 4 bination with atesting plug ordevice hav-ing two insulated contact-points connected by a loop in which is a battery anda test-receivling instrument, said plug contact-points being adaptedto be brought into contact with any pair Vof said test-bolts, whereby thel operator' may'determine whether or ,not eitherotf said lines is in use. 4

6. In a telephouevsystem, a telephone-linel grounded at its two ends, a switching devicev in thecircuit of said line, adapted to openand closesaid line inthe operation ot thesystem,

at the contact-points, and a pair of test-bolts, one ofthe bolts' being connected to theline on one side of ttheswitching device and theY other bolt being connected Ito the line on the other side of the switching device, in Vcombination with an,o `erators testing s 7stem consistin .c D Y 7 roo Y of atesting plug or device, with twocontactpieces, a battery, a test-receiving instrument, andaloop, said contact-pieces being connected by the loop andl adapted toA be broughtinto contact with said test-bolts, said loop contain-f,

ing said battery and test-receivinginstrument,

and said battery andte'st-receiving instrument l being so adjusted to each other that the instrument will respondwhen the testing deviceis applied to the test-bolts and t-heV circuit betweenthe bolts is closed at the switching de-V vice, but will not respond whenthe circuit is open at the switching device, substantially as and for the purpose set forth. Y

7. Ina telephoneexchange system, two or more switch-boards provided 4with series of switches, one series for each lineA and one switch of each series arranged on each board, each line passing through each switch of its series and to, ground, switch-plugs adapted to IIO be inserted into any of said switches, and when f inserted to open the line at thecontact-points of the switch and disconnectit from the ground,

and series of pairs of test-bolts, one series Afor each line and one pair of each series on each4 board, one bolt of; each pair'being connected to its line before it is y.connected to .any of :its-

sw'itches, 4and the'other bolt being connected., toits line .after it.. has passed through its switches and before it is connected to the. ground, in combinationwith operators. testing systems, one system at each board, and each consisting ofa testing plug or device, with two contact-points, a battery, a test-receiving instrument, and a loop, said contactpoints being connected. to the loop and being adapted to be brought into contact with any pair of the test-bolts at the board, and said loop containing thebattery and test-receiving instrument, whereby the operator at any board may by a preliminary test determine whether any line is in use.

8. The combination of two or more strips of insulating material placed one above the other and each having the metal parts of spring-jack switches mounted thereon, with rectilinear plug-holes, one for each of said switches and transverse to the front and along one of the edges of its strip, whereby the edge of one strip provides one of the sides of the holes of another strip, substantially as and for the purpose set forth.

9. In a telephone exchange system, two subscribers lines temporarily connected together for conversation, in combination with a calling generator or battery, a clearing-out annunciator, an operators telephone, a calling-key,and a switching device, said key and said generator being n a wire or circuit grounded'on one side and connected to the circuit of said lines on the other side, said operator-s telephone and said clearing-out annunciator being each in a loop, the two ends of which are connected to the two contactbo1ts of a pair of contact-bolts of said switching device, (there being one pair of contactbolts for each loop,) said switching device having two contactpieces, each connected to its side of the circuit of said lines, and the two contactpieces being adapted to be brought into connection with either pair of, said bolts, whereby at the will of the operator he may loop either the operators telephone or the clearing'out annunciator into the circuit of the lines so connected together, and may ground said circuit through the calling generator, substantially as set forth.

10.' In a telephone exchange system, two subscribers lines temporarily connected together for conversation, in combination with annunciator, 'a calling-key, and a switching device, said key and said generator being in a wire or circuit grounded on one side and connected to the circuit of said lines on the other side, said clearing-out annunciator being in a two contact-bolts of said switching device, said switching device having two contact-pieces, each connected to its side ofthe circuit of said lines, and said contact-pieces being adapted to be brought into connection with said bolts, whereby at the will of the operator he may loop the clearing-out annunciator in and out of the circuit of thelines so con nccted together, and may ground said circuit through the calling-generator, substantially as set forth.

11. In an operators cord system, two cords normally (or when their plugs are not in lincswitches) grounded, in combination with an operators telephone, a callinggenerator, a calling-key', and a switching device, said key and said generator being in a wire or circuit grounded on one side and connected to the circuit of said lines on the other side, said telephone being in a loop, the two ends of which switching device, said switching device having two contact-pieces, either connected to its one of said cords, and said contact-pieces being adapted to be brought'into connection with said bolts,whereby at the will of the operator he may loop said telephone into and out of the cuit through the calling-generator, substantially as set forth.

MILO G. KELLOGG.

Vitnesses:

CALVIN DE WOLF, WALLACE L. DE WOLF.

a calling generator or battery, a clearing-out u loop, the two ends of which are connected toi are connected to two contact-bolts of said circuit of the cords, and may ground said cir' 

